A solar wind stream flowing from this sprawling northern coronal hole could reach Earth as early as Oct.12-13. Credit: SDO/AIA.

Noctilucent CloudsThe northern season for NLCs is finished. According to NASA's AIM spacecraft, the last clouds were observed over Greenland on Aug. 27th. Now the waiting begins for the southern season expected to begin in November.

Geomagnetic Storms:Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm

Updated at: 2015 Oct 12 2200 UTC

Mid-latitudes

0-24 hr

24-48 hr

ACTIVE

30 %

35 %

MINOR

10 %

20 %

SEVERE

01 %

05 %

High latitudes

0-24 hr

24-48 hr

ACTIVE

15 %

10 %

MINOR

35 %

30 %

SEVERE

40 %

55 %

Monday, Oct. 12, 2015

What's up in space

Marianne's Heaven On Earth Aurora Chaser Tours Chasethelighttours.co.uk invites you to join them in their quest to find and photograph the Aurora Borealis. Experience the winter wonderland in the Tromsø Area.

AFTER LAST WEEK'S "MASSIVE AURORAS," WHAT WILL THIS WEEK BRING? Arctic sky watchers are still buzzing about last week's 3-day outburst of Northern Lights. Many veteran observers ranked it as the brightest display they had seen in years. Photographer Ole Salomonsen was one of them. "On Friday, Oct. 9th, I was treated with perhaps the most massive aurora I have ever witnessed," he says. "They appeared right over my hometown, Tromsø, Norway."

"The auroras were so strong that many of my shots were overexposed," he continues. "I had to continuously lower the exposure not to burn out the auroras. I have never in my life witnessed this amount of pink auroras, just MASSIVE!"

The display was caused by shock waves from a CIR (co-rotating interaction region), which hit Earth on Oct. 7th, followed by a stream of high-speed solar wind on Oct. 8th and 9th. Strong geomagnetic storms sparked Northern Lights as far south as Virginia, USA.

Another stream of solar wind is coming. ETA: Oct.12-13. Without another CIR to "pre-condition" Earth's magnetic field, however, this week's solar wind stream will probably have less effect. NOAA forecasters estimate a 60% chance of minor G1-class geomagnetic storms on Oct.12th. Aurora alerts: text or voice

MORNING SKY SHOW, IT'S ABOUT TO GET BETTER: All month long, "morning people" have been watching planets converge in the pre-dawn sky. Venus, Jupiter, and Mars are all visible in the east before sunrise. Pete Lawrence sends this picture from a beach in Selsey, West Sussex, UK

"This was the view at daybreak on Oct. 9th," says Lawrence. "Venus, Mars and Jupiter gathered together with the crescent Moon. What a great way to start the day!"

The view is about to get even better. For the rest of the month, the planets will draw closer and closer together until Oct. 24th - Oct. 29th when they fit within a circle only 5o wide (sky maps: #1, #2, #3, #4, #5, #6). Typical binoculars can see a patch of sky about 6o or 7o degrees wide. So when the triangle of planets shrinks to 5o, they will all fit inside a binoculars field of view. Imagine looking through the eyepiece and seeing three planets--all at once.

By the time October comes to an end, the planetary triangle will start breaking apart. But there are still two dates of special interest: Nov. 6th and 7th (sky maps: #1, #2). On those increasingly wintry mornings, the crescent Moon will swoop in among the dispersing planets for a loose but beautiful conjunction.

These measurements are based on space weather balloon flights, described below.

Introduction: Once a week, and sometimes more often, Spaceweather.com and the students of Earth to Sky Calculus fly "space weather balloons" to the stratosphere. These balloons are equipped with radiation sensors that detect cosmic rays, a form of space weather important to people on Earth. Cosmic rays can alter the chemistry of the upper atmosphere, seed clouds, spark exotic forms of lightning, and penetrate commercial airplanes. This last point is of special interest to the traveling public. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. From now on we will present the results of our regular weekly balloon flights in this section of our web site. Here is the radiation profile from our latest flight:

Radiation levels peak at the entrance to the stratosphere in a broad region called the "Pfotzer Maximum." This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are nearly 100x sea level.

Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Sept. 27th measurements, a plane flying at 45,000 feet is exposed to 288 uRads/hr. At that rate, a passenger would absorb about one dental X-ray's worth of radiation in 5 hours.

Stay tuned for improvements to this section in the days and weeks ahead as we develop a glossary and better plain language strategies for communicating this information. Suggestions are welcomed.

All Sky Fireball Network

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.